As far as full synthetics go, I have only used two. Mobile 1 and this Castrol. No complaints on either. I was surprised to find the condition of the Castrol as good as it was when I drained it. Now that was only at a 2000 mile interval but I road it exceedingly hard, ehr.....over the speed limit by quite a bit, for 5 consecutive hours each way on a trip to Barbers over the weekend. Didn't use any oil and the oil looked to have plenty of life left.

I will also add that I chose the 50w based on where I live. Those north of the Mason-Dixon may want to get the 40W.